Box 2.

Open questions and future opportunities in CNS fibroblast research. 

Development • How are CNS fibroblasts different from fibroblasts in other tissues? • Do CNS fibroblast subtypes have a single common lineage? • What are the key regulators of CNS fibroblast differentiation? • Are there specific markers of CNS fibroblasts? Physiological function • How do fibroblasts transduce information between the external milieu and the brain parenchyma? • Do different CNS fibroblasts subtypes have different functions? • How is the “fibroblast-immune cell niche” organized in the meninges, perivascular space, and choroid plexus? • Do fibroblasts contribute to CSF waste clearance? • Through what signaling mechanisms do fibroblasts communicate with astrocytes, microglia, and neurons following CNS injury or infection? • Can scar-forming fibroblasts be transformed into functional cells to repair CNS injury? • Do fibroblasts play a role in glioblastoma? • How does fibroblast signaling affect the progression of neurodegenerative diseases?